we have many folders which contains 96 files like: A01 to A12, B1 to B12,C1 to C12,D1 to D12,E1 to E12, F1 to F12,G1 to G12,H1 to H12.. We also have shown the A series files of folder number 1635.... A01_Wgenome0011P3_2013-05-18_015 A02_Wgenome0011P3_2013-05-18_016 A03_Wgenome0011P3_2013-05-18_031 A04_Wgenome0011P3_2013-05-18_032 A05_Wgenome0011P3_2013-05-18_047 A06_Wgenome0011P3_2013-05-18_048 A07_Wgenome0011P3_2013-05-18_063 A08_Wgenome0011P3_2013-05-18_064 A09_Wgenome0011P3_2013-05-18_079 A10_Wgenome0011P3_2013-05-18_080 A11_Wgenome0011P3_2013-05-18_095 A12_Wgenome0011P3_2013-05-18_096 same is the case with other series I,e.BCDEFGH all I want to rename these file names in following format. TaeCsp2AS_1635A01 TaeCsp2AS_1635A02 TaeCsp2AS_1635A03 TaeCsp2AS_1635A04 TaeCsp2AS_1635A05 TaeCsp2AS_1635A06 TaeCsp2AS_1635A07 TaeCsp2AS_1635A08 TaeCsp2AS_1635A09 TaeCsp2AS_1635A10 TaeCsp2AS_1635A11 TaeCsp2AS_1635A12

so please suggest me some command or script to do it........thanks in advance

Laurent's suggestion is excellent if you only have to run this job a few times. If you have many directories, or if you will have to repeat it in the future, I recommend a more robust solution. (If for no other reason, a "one-liner" increases the risk due to typing errors.)

It may be overkill in your case, but a production version of this program should include a great deal of error detection and possibly recovery.

Verify that the directory exists.

Set the working directory to it

Verify that it contains all required files (and no others)

Create a temporary directory

Copy the required files to the .temp directory

Verify that the copy is correct

Rename the files in the temp directory

Verify that the rename succeeded.

Optionally delete the original files and copy the new ones back into the original directory.

Note that, at least on Unix, this is not exactly the same as renaming the files. This algorithm would lose all of the original file times Good Luck, Bill